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CHAPTER 6

Measuring the Friction of Air Bearings

Aerostatic linear bearings have two major features: (1) high accuracy of motion and (2) low friction. The first is widely exploited, together with linear motors, in the most precise machine tools and instruments, and has been studied. The second, low friction, attracted little attention because there was no way to measure it. Yet it will become a central concern for improving the accuracy of motion control.

Because the LMM measures the motion of the bearing's moving part with an optical interferometer, the force acting on the moving part, that is, the friction inside the bearing, can be evaluated directly. Forces at the 10 mN level are handled.

• Y. Fujii, H. Fujimoto, "Measurements of frictional characteristics of a pneumatic linear bearing", Meas. Sci. Technol., Vol.10, No.5, pp.362–366, 1999.
• Y. Fujii, "Measurement of force acting on a moving part of a pneumatic linear bearing", Rev. Sci. Instrum., Vol.74, No.6, pp.3137–3141, 2003.
• Y. Fujii, "An optical method for evaluating frictional characteristics of linear bearings", Opt. Lasers Eng., Vol.42, No.5, pp.493–501, 2004.
• Y. Fujii, "Frictional characteristics of an aerostatic linear bearing", Tribol. Int., Vol.39, No.9, pp.888–896, 2006.

← Previous: 5. Dynamic Error Correction | Next: 7. Material Testing and Micro-Force →

Contents

• Home
• 1. Principle
• 2. Why It Is Needed
• 3. Space Balance
• 4. Dynamic Calibration
• 5. Dynamic Error Correction
• 6. Air-Bearing Friction
• 7. Material Testing and Micro-Force
• 8. Biomechanics and Impact
• 9. Measurement Techniques
• 10. Papers
• 11. Contact

The Levitation Mass Method: precision force measurement by the definition of force | Yusaku Fujii (Gunma University)